#include<bits/stdc++.h>
using namespace std;
int n,fruit[200005];
struct node{
	int st,ed,edval;
};
queue <node> q,fruits;
bool vis[200005];
void merge(){
	while(!q.empty()){
		node now1=q.front();
		q.pop();
		while(!q.empty()){
			node now2=q.front();
			if(now1.edval==now2.edval){
				now1.ed=now2.ed;
				q.pop();
			}else{
				break;
			}
		}
		fruits.push(now1);
	}
}
int main(){
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>fruit[i];
	}
	int st=1,cnt=n;
	for(int i=2;i<=n;i++){
		if(fruit[i]!=fruit[i-1]){
			fruits.push(node{st,i-1,fruit[i-1]});
			st=i;
		}else if(i==n){
			fruits.push(node{st,n,fruit[n]});
		}
	}
	while(cnt){
		while(!fruits.empty()){
			node now=fruits.front();
			fruits.pop();
			while(vis[now.st] && now.st<=now.ed){
				now.st++;
			}
			if(now.st>now.ed){
				cout<<now.st<<" ";
				vis[now.st]=1;
				cnt--;
				if(now.st!=now.ed){
					now.st++;
					q.push(now);
				}
			}
		}
		cout<<endl;
		merge();
	}
	return 0;
}